asp调用数据表代码

代码1： <% Set conn=Server.CreateObject("ADODB.CONNECTION")
Set rs=Server.CreateObject("ADODB.RecordSet")
conn.open Application("sjjh_usermdb")
rs.Source= "Select top 20* from dbo_gongzuo Order By id DESC"
rs.Open rs.Source,Conn,1,1
do while not rs.eof
i=i+1%>
<li><a href="../gongzuo/<%=rs("a") %>" target="_blank"><%=rs("b") %></a></li>
<%if i=20 then exit do
RS.MoveNext
Loop
rs.close
set rs=nothing
conn.close
set conn=nothing
%>代码2： <%
Set conn=Server.CreateObject("ADODB.CONNECTION")
Set rs=Server.CreateObject("ADODB.RecordSet")
conn.open Application("sjjh_usermdb")
rs.Open"Select top 20* from dbo_gongzuo Order By id DESC",Conn,1,1
do while not rs.eof
i=i+1
%>
<li><a href="../gongzuo/<%=rs("a") %>" target="_blank"><%=rs("b") %></a></li>
<%
if i=20 then exit do
rs.movenext
loop
set rs=nothing
conn.close
set conn=nothing
%>代码3:
<%
Set conn=Server.CreateObject("ADODB.CONNECTION")
Set rs=Server.CreateObject("ADODB.RecordSet")
conn.open Application("sjjh_usermdb")
const MaxPerPage=20
dim totalPut
dim CurrentPage
dim TotalPages
dim i,j
%>
<%dim sql
dim rs
dim filename
sql="Select top 20* from dbo_gongzuo Order By id DESC"
rs.open sql,conn,1,1
if rs.eof and rs.bof then
response.write "<p align='center'>没有可排行的对象</p>"
else
%>
<table width="960" border="1" align="center" cellpadding="0" cellspacing="1" bordercolor="#000000" bordercolorlight="#000000"
bordercolordark="#FFFFFF">
    <tr bgcolor="#FFCC00">
      <td align="center" width="88" >姓名</td>
      <td align="center" width="88" >类别</td>

</tr>
<%do while not rs.eof%>
<tr ">
<td align="center" width="88" ><%=rs("a")%></td>
<td align="center" width="88" ><%=rs("b")%></td>
</tr>
<%
rs.movenext
filename=filename+1
if filename>19 then Exit Do
loop
end if
rs.Close
set rs=nothing
conn.close
set conn=nothing
%>
</table>
以上3种代码都能实现调用数据表前20选项。
哪种效率更高呢？对资源消耗更小？